In general, there is known a heat transfer device including a heat pipe in which working fluid is enclosed in a container, a heat receiving section being provided on one end side of the heat pipe and a heat radiating section being provided on the other end side of the heat pipe. In the heat transfer device of this type, the working fluid repeats evaporation and condensation and refluxes in the container, whereby heat transfer is performed. That is, the working fluid evaporates on the heat receiving section side in the container and the evaporated working fluid moves to a heat radiation side in the container according to a pressure difference. The evaporated working fluid is condensed on the heat radiation side to be liquid. The working fluid refluxes to the heat receiving section side with capillarity of a wick provided on the inner wall of the container. In this way, in the heat transfer device including the heat pipe, the apparent heat conductivity of the container is approximately several times to several ten times more excellent than the apparent heat conductivity of metal such as copper or aluminum. Therefore, the heat transfer device is mounted on an electronic apparatus such as a personal computer and used for cooling of cooling target components such as a CPU.
Incidentally, depending on a position of the heat receiving section where the cooling target component is provided, the heat pipe of this type is classified into top heat in which the heat receiving section is disposed in an upper part in the gravity direction and bottom heat in which the heat receiving section is disposed in a lower part in the gravity direction. When the heat pipe is disposed in the top heat, since the reflux of the working fluid to the heat receiving section present in a high position is prevented by the gravity, a heat transfer amount greatly decreases.
As a method for solving this problem, there has been proposed a configuration in which a vibrator is attached to the heat pipe to assist the reflux of the working fluid to the heat receiving section provided upward in the gravity direction (see, for example, Patent Literature 1).